Despite the invaluable properties and broad applications of synthetic elastomers, the management of waste rubbers and end-of-life tires typically involves mechanical recycling or conversion into low-grade fuel. This study introduces an effective and selective chemical recycling method for synthetic elastomers, including polybutadiene, polycycloalkenamers, and their copolymers, utilizing a synergistic tandem catalysis approach that combines isomerization and ring-closing metathesis. By exploiting the ring-chain equilibrium of oligomers, we have demonstrated the selective depolymerization of rubbers into C5–C7 cycloalkenes. Importantly, this method effectively depolymerizes post-consumer vulcanized rubbers, such as disposable rubbers and tires, converting them into highly valuable chemical feedstocks. These results highlight the significant potential of tandem dual catalysis for the selective chemical recycling of synthetic rubbers.